Still, it's been pointed out in the books that even for people with huge lifespans, raising your Essence is kind of a big thing; most Immaculates of even the proper age don't raise it that high without serious adjustments to their very lifestyle.
I'd also like to point out that Terrestrials aren't really that common; there's less than a hundred thousand of them in all of Creation - heck, the South book goes entire chapters without naming any.